This invention relates generally to the field of telecommunications systems, and more particularly to a protection architecture for virtual channel connections (VCCs) in a telecommunications network.
Telecommunications networks have traditionally been circuit-switch networks that have transmission paths dedicated to specific users for the duration of a call and that employ continuous, fixed-bandwidth transmission. Due to growth in data traffic created by the Internet and its related technologies, however, core telecommunications networks are being moved to a packet-switching transmission model. Packet-switch networks provide a large range of digital services, from data to video to basic voice telephony. Packet-switch networks can allow dynamic bandwidth and may be connectionless with no dedicated path or connection-oriented with virtual circuits and dedicated bandwidth along a predetermined path.
Asynchronous transfer mode (ATM) is a connection-oriented packet-switching technology in which information is organized into small, fixed length cells. ATM carries data asynchronously, automatically assigning data cells to available time slots on demand to provide maximum throughput. Compared with other network technologies, ATM provides large increases in maximum supported bandwidth, designed-in asynchronous traffic support, support for multiple types of traffic such as data, video, and voice transmissions on shared communication lines, and virtual networking capabilities, which increase bandwidth utilization and ease network administration.
ATM cells are routed through a telecommunications network at high speeds using a switching label included in the cell. The switching label has two sections that define a virtual path (VP) and a virtual channel (VC) in the network through which the cell is routed. The use of virtual paths (VPs) and virtual channels (VCs) allows physical bandwidth in the network to be subdivided into virtual channel connections (VCCs) and separately commercialized.
Within a telecommunications network, virtual channel connections (VCCs) are typically routed along redundant paths to support protection switching at a destination node. As bandwidth in transmission lines is subdivided into an increasing number of virtual channel connections (VCCs), however, protection switching for each of the connections becomes difficult to implement. Previous attempts to manage protection switching have included bundling together virtual channel connections (VCCs) to form a virtual channel group (VCG) In the event of protection switching, all virtual channel connections (VCCS) contained within the group are simultaneously switched. Although this improves efficiency, switching nevertheless remains at the virtual channel connection (VCC) level and is resource intensive.
The present invention provides a protection architecture for virtual channel connections (VCCs) in a telecommunications network that substantially eliminate or reduce disadvantages and problems associated with previous systems and methods. In particular, virtual channel connections (VCCs) for a protection domain are bundled together into a virtual path connection (VPC) and protection switched at that level in the event of a transmission line failure.
In accordance with one embodiment of the present invention, a method for protecting virtual channel connection (VCC) traffic in a telecommunications system includes receiving a virtual path connection (VPC) at a destination node. The virtual path connection (VPC) is received on each of a working transmission link and a protection transmission link. The virtual path connection (VPC) includes a plurality of virtual channel connections (VCCs). A protection switching status is received for each of the working and protection transmission links. The virtual channel connections (VCCs) are selected from the working and protection transmission links for processing by selecting the virtual path connection (VPC) from one of the working and protection transmission links based on the protection switching status for at least one of the working and protection transmission links.
More specifically, in accordance with a particular embodiment of the present invention, a virtual path group (VPG) is received on each of the working and protection transmission links at the destination node. The virtual path group (VPG) includes the virtual path connection (VPC). The virtual path connection (VPC) is selected from the working and protection transmission links by selecting the virtual path group (VPG) from one of the working and protection transmission links based on the protection switching status for at least one of the working and protection transmission links. In this embodiment, the virtual path group (VPG) may be selected from the protection transmission link in response to receiving an alarm indication signal (AIS) for the working transmission link.
Technical advantages of the present invention include providing an improved protection architecture for virtual channel connections (VCCs) in a telecommunications network. In particular, virtual channel connections (VCCs) are bundled together into a virtual path connection (VPC) that can be protection switched as a unit in response to a transmission line failure. Accordingly, only a single construct needs to be protection switch and pathway selection is simplified at the terminus of the virtual channel connections (VCCs). In addition, configuration and management at intermediate nodes is simplified because many virtual channel connections (VCCs) are tunneled into a single construct and the intermediate nodes see only the construct.
Other technical advantages of the present invention will be readily apparent to one skilled in the art from the following figures, description, and claims.